Truing mechanism for grinding wheels

ABSTRACT

This disclosure relates to a truing mechanism for grinding wheels. A principal feature of the truing mechanism is that the truing roller is in the form of a relatively thin wheel having an axis of rotation parallel to the axis of rotation of the grinding wheel being trued. As a result, it is possible to rotate the truing roller during a first pass across the grinding wheel to perform a rough truing operation and to hold the truing roller stationary during a return pass, even across the rounded corners of the grinding wheel, to perform a light and highly desirable fine finish truing operation.

United States Patent [72] lnventor William P. Flohr. Jr.

Waynesboro, Pa. [21] AppLNo 751,152 [22] Filed Aug. 8,1968 [45] PatentedJune 15. 1971 [73] Assignee Landis Tool Company Waynesboro, Pa.

[54] TRUING MECHANISM FOR GRINDING WHEELS 10 Claims, 7 Drawing Figs.

[52] US. Cl 125/11 [51] Int. Cl t t B24b 53/00 [50] Field of Search125/11; 51/161 [56] References Cited UNlTED STATES PATENTS 2,528,62111/1950 Sweetser 125/11 X 2,664.681 1/1954 Clark.. 3.313.285 4/1967Price...

Primary Examiner-Harold D, Whitehead All0rney-Diller, Brown, Ramik andHolt ABSTRACT: This disclosure relates to a truing mechanism forgrinding wheels. A principal feature of the truing mechanism is that thetruing roller is in the form of a relatively thin wheel having an axisof rotation parallel to the axis of rotation of the grinding wheel beingtrued. As a result, it is possible to rotate the truing roller during afirst pass across the grinding wheel to perform a rough truing operationand to hold the truing roller stationary during a return pass, evenacross the rounded corners of the grinding wheel, to perform a light andhighly desirable fine finish truing operation.

PUMP

PATENTEDJUNISIHYI 3,584,616

UJILUHM P. FLOHR,Jr.

ATTORNEYS PATENIED JUN] 5197:

SHEET 3 OF 3 6 REVERSE M.

INVENTOR (AMLUAM P4 FLOHR,Jr.

BY GM; 35g

TRUING MECHANISM FOR GRINDING WHEELS This invention relates in generalto new and useful improvements in truing mechanisms for grinding wheels,and more particularly to a truing mechanism which will permit a finetruing operation across the entire operative face of the grinding wheel,including the rounded corners thereof.

In the past it has been found that a single diamond truing device willproduce a much finer surface on a grinding wheel. On the other hand, thelife of a single diamond truing device is relatively short andtherefore, on production grinders it is desirable to utilize a truingroller.

In order to not sacrifice the quality of finish obtainable with a singlediamond, in the past, during the return truing operation, the truingroller has been held stationary as it passes across the peripheral faceof the grinding wheel. However, it has not been possible to hold thetruing roller stationary as it passes around the rounded corners of thegrinding wheel due to the relationship of the truing roller relative tothe grinding wheel.

In accordance with this invention, there is provided a novel truingmechanism wherein the relationship of the truing roller with respect tothe grinding wheel is such that the truing roller may be held stationaryduring the entire return pass thereof across the grinding wheel wherebythe truing roller is stationary not only as it passes across theperipheral face of the grinding wheel, but also as it passes around therounded comers thereof.

A principal feature of this invention is the provision of a truingroller which has an axis of rotation parallel to the axis of thegrinding wheel being trued.

Another feature of this invention is to provide a truing roller which isvery thin as compared to the thickness of the grinding wheel beingdressed and at the same time is of a large diameter as compared toexisting truing rollers whereby the desired relationship between thetruing roller and the grinding wheel to effect a fine truing operationon the grinding wheel and at the same time to provide for the desiredlong life of the truing roller.

Another feature of this invention is to provide in a truing mechanismfor a grinding wheel a profiling assembly which includes a fixed profileand a cooperating follower, the follower having sliding contact with theprofile and being of a size and shape corresponding to the size andshape of the peripheral portion of the associated truing roller.

Another feature of this invention is the utilization of a highlydesirable friction type brake for quickly and effectively stopping therotation of the truing roller at the end of one pass thereof across agrinding wheel and to retain the truing roller in such fixed positionduring the return pass thereof.

With the above and other objects in view that will hereinafter appear,the nature of the invention will be more clearly understood by referenceto the following detailed description, the appended claims and theseveral views illustrated in the accompanying drawings:

IN THE DRAWINGS FIG. I is a schematic plan view showing the operationalenvironment of the truing mechanism of this invention.

FIG. 2 is a fragmentary enlarged side elevational view of the grindingwheel of FIG. 1 and shows specifically the details of the truingmechanism.

FIG. 3 is an elevational view of the truing mechanism of FIG. 2, asviewed from the left side thereof with parts broken away and shown insection.

FIG. 4 is a fragmentary horizontal sectional view taken along the line4-4 of FIG. 3 and shows specifically the mounting ofthe truingmechanism.

FIG. 5 is a fragmentary sectional view taken along the line 5-5 of FIG.3 and shows specifically the details of the brake mechanism.

FIG. 6 is a fragmentary vertical sectional view taken along the line 6-6of FIG. 5 and shows further the details of the brake mechanism.

FIG. 7 is a schematic showing the relative movement of the truing rolleras compared with a profile for controlling the movement thereof.

Referring now to the drawings in detail, reference is made first to FIG.ll wherein the general environmental structure of the truing mechanismis illustrated. It will be seen that the truing mechanism, which isgenerally referred to by the numeral 10, has the diamond impregnatedtruing roller 1 I thereofillustrated in engagement with a grinding wheel12 and performing a truing operation thereon. The movement of the truingroller 11 relative to the grinding wheel 12 is controlled by a fixedprofile 13 which is engaged by a follower assembly 14 including afollower 15 which is in direct sliding contact with the profile 13 andwhich is of the same width as the truing roller 11 and has an endcontour corresponding to the peripheral contour ofthe truing roller II.

The manner in which the truing mechanism 10 is operated is morespecifically disclosed in the commonly assigned U.S. Pat. No. 3,121,423of Ralph E. Price, et al. granted Feb. 18, I964. Accordingly, there willbe described here only such operation of the mechanism for shifting andpositioning the truing mechanism 10 as will be necessary to understandthe invention.

The truing mechanism 10 is mounted on a truing bar 16 which is carriedby a slide I7 for movement toward and away from the axis of the grindingwheel 12. The slide 17, in turn, is slidably mounted on a carriage 18which is mounted for traverse movement parallel to the axis of thegrinding wheel 12. The carriage 18 is mounted on a suitable portion ofthe bed (not shown) of the grinding machine of which the grinding wheel12 is a part.

The truing mechanism 10 is advanced and retracted by means ofa cylinder20 which is secured to the slide 17 and in which there is positioned apiston 21. The piston 21 has a piston rod 22 coupled to the carriage 18.The piston 21 and the cylinder 20 normally function to hold the follower15 in engagement with the profile 13. The actuation of the cylinder 20is controlled by means ofa valve 23 which is connected to a suitablepressure pump 24. The valve 23 is, in turn, actuated by suitablesolenoids 25 and 26.

Traversing movement of the carriage 18 is effected by means of a piston27 which is mounted within a cylinder 28. The piston 27 has a piston rod29 connected to the carriage 18. The movement of the piston 27 iscontrolled by means ofa conventional valve 30 which is connected to thepump 24 for receiving fluid under pressure therefrom. The valve 30 isactuated and positioned by means of a pair of solenoids 3i and 32 in aconventional manner.

Referring now to FIGS. 2 and 4 in particular, it will be seen that thetruing mechanism It) includes a rigid frame 33 of a suitableconfiguration. The frame 33 is removably secured to the truing bar 16 bymeans of a plurality of fasteners 34.

As is best shown in FIGS. 3 and 4, the lower portion of the frame 33supports a spindle assembly 35 which includes mounting cars 36 havingslotted openings 37 therein receiving fasteners 38 which secure thespindle assembly to the frame 33.

The spindle assembly 35 includes a shaft 40 which is mounted forrotation and which is firmly supported so as to be free of vibrations.One end portion of the shaft 40 has mounted thereon the truing roller 11while the other end of the shaft 40 is provided with a dual groovedpulley 41 for effecting the driving of the shaft 40.

The upper portion of the frame 33 is provided with a motor support 39,the upper portion of which has mounted thereon a motor bracket 39Asupporting a power unit 42 which is preferably in the form of anelectric motor, but which may be in the form of any desired type ofpower unit. It is to be understood that the power unit 42 is of aconventional type and is mounted on the motor bracket 39A in a mannerwherein it may be vertically adjusted. The power unit 42 is providedwith a dual grooved pulley 43 which is aligned with the pulley 41 andwhich is drivingly connected thereto by means of belts 44. It is to benoted that the pulleys 41 and 43 and the belts 44 are encased within ahousing 45.

The frame 33 also has secured thereto a coolant head 46 for distributingcoolant on the truing roller 11 and the grinding wheel 12 during atruing operation. A coolant supply line 47 is suitably connected to thecoolant head 46.

The truing mechanism also includes a brake which is generally referredto by the numeral 48 (FIG. 3). The brake functions to both stop therotation of the truing roller 11 and to hold the truing roller 11against rotation during one part of a truing operation on a grindingwheel. Basically, the brake 48 includes a brake drum 49, which ismounted on the shaft 40 adjacent to and outwardly of the truing roller11, and a pair of opposed shoes 50 and 51 which are engageable with thebrake drum 49 in diametrically opposed relation.

Referring now to FIG. 6 in particular, it will be seen that the brake 48is carried by a mounting plate 52 which is adjustably secured to theframe 33 by means of a plurality of fasteners 53 to assure the alignmentof the shoes 50, 51 with the brake drum 49. The mounting plate 52 hasmounted thereon for pivotal movement a pair of shoe supports 54 and 55which are best illustrated in FIG. 5. The shoe support 54 carries theshoe 50 while the shoe support 55 carries the shoe 51 with the shoesupports 54 and 55 being pivotally mounted on pivots 56 and 57,respectively.

In order that the shoes 50 and 51 may move in unison, the shoe supports54 and 55 are interconnected. It is to be noted that the shoe supports54 and 55 have overlapping end portions 58 and 60, respectively. The endportion 60 carries a hardened ball 61 which is engaged with a hardenedinsert 62 carried by the end portion 58.

At this time it is pointed out that the shoes 50 and 51 are constantlyurged away from the brake drum 49 by means of a tension spring 63 whichis coupled to the shoe support 54. The spring 63 urges the shoe 511 in acounterclockwise direction with the result that the hardened insert 62will move to the right, moving the ball 61 to the right and urging theshoe 51 in a clockwise direction.

The shoes 50 and 51 are moved into contact with the brake drum 49 bymeans of a lever 64 which is secured to the shoe support 55 and which isactuated in a manner to be described hereinafter. It is to be noted thatthe lever 64, when actuated, urges the shoe 51 in a counterclockwisedirection. At the same time, the ball 61 will move to the left, movingthe insert 63 to the left and effecting clockwise movement of the shoe50 into engagement with the brake drum 49.

It is to be understood that the structure of the shoe supports 54 and 55may vary. In a like manner, the construction and attachment of the shoes50 and 51 may vary. Accordingly, no attempt has been made to show thespecific details thereof. On the other hand, it is pointed out that itis preferred the shoe support 55 be of a two-piece construction with thetwo pieces being connected together by fasteners whereby the angularrelationship of the two pieces of the shoe support 55 may be slightlyvaried so as to assure simultaneous contact of the shoes 50 and 51 withthe brake drum 49.

Referring now to FIGS. 2 and 3 in particular, it will be seen that thereis secured to the central portion of the frame 33 a fluid motor 67. Thefluid motor 67 includes a combination bracket and cylinder 66 and isattached to the frame 33 by means of the bracket. The fluid motor 67also includes a piston 69 which is positioned within the cylinder 66 forrelative axial movement. The lever 64 is provided with an adjustable pin70 which engages the exposed end of the piston 69 eccentrically of thecenter thereof.

Fluid is supplied into the cylinder 66 through a fitting 71. When fluidunder pressure is directed into the cylinder 66, the piston 69 will moveto the right, as is shown in FIG. 2, swinging the lever 64 in aclockwise direction so as to actuate the brake 48. It is to be notedthat the lever 64 is normally retained in a brake releasing position bymeans of a tension spring 72 which has one end connected to the upperend of the lever 64 and the opposite end connected to the cylinder 66.It is also to be noted that the tension spring 63 is connected to thecylinder 66.

At this time it is pointed out that the brake drum 49 is in the form ofa detachable sleeve which is suitably mounted on the shaft 40 in anydesired manner. The brake drum 49 and the truing roller 11 are readilyremovable from the shaft 40 by the removal ofa retaining nut 73 which isclearly shown in FIG. 3. It will be readily apparent from FIGS. 3 and 4that the truing roller is in the form of a relatively thin wheel. Inactual practice the wheel has a width of 0.1875 inch and a diameter onthe order of 3 inches. In addition, it is to be noted that the truingroller has rounded corners. These rounded corners not only facilitatethe proper truing of the rounded corners of the grinding wheel 12, butalso facilitate the movement of the follower 15 around the contours ofthe profile 13, as is best shown in FIG. 7. It is to be noted that thecontour of the follower 15, which corresponds to that of the truingroller 11, is clearly shown in FIG. 7.

Referring once again to FIG. 1, it will be seen that the operation ofthe brake 48 is controlled by means ofa valve 75. The valve 75 issuitably connected to the pump 24 and the actuation thereof iscontrolled by a solenoid 76.

At this time it is also pointed out that the actuation of the valve 30for controlling the transversing of the carriage 18 may be controlled bysuitable limit switches, such as the limit switch 77 which is operableby means of an abutment 78 carried by an extension of the carriage 18.In addition, it is to be noted that the limit of retraction of the slide17 may be controlled by a limit switch 80 which is engaged by anabutment 81 carried by the slide 17.

OPERATION Referring now generally to FIGS. 1 and 7, it is to be understood that the truing roller 11 will normally be disposed in aretracted position at one side of the grinding wheel 12. At this timethe follower 15 will be out of contact with the profile 13. When it isdesired to initiate the truing operation, the solenoid 31 will beactuated to shift the valve 30 to a position where fluid is directedinto the left hand end of the cylinder 28, thereby moving the carriage18 to the right until the follower 15 is aligned with the profile 13adjacent a corner portion thereof. Then with the truing roller 11 beingrotated by the power unit 42, the valve 23 directs fluid into thecylinder 20 so as to urge the slide 17 toward the grinding wheel 12 withthe result that the follower 15 comes into contact with the profile 13and the truing roller 11 engages the grinding wheel 12 at the left-handcorner thereof. Then, while the slide 17 is still urged toward thegrinding wheel 12, the valve 30 is actuated to move the carriage 18 tothe right with the result that the follower 15 moves around theleft-hand corner of the profile 13 for the truing roller 11 to dress theleft-hand corner of the grinding wheel 12. Then the carriage 18 is movedfurther to the right with the peripheral face of the grinding wheel 12being trued. Thereafter, as the carriage 18 continues to move to theright, the right-hand corner of the grinding wheel 12 is trued. When thecarriage and slide reach a predetermined point in the truing of theright-hand corner of the grinding wheel 12, the movement of the carriage18 is reversed. At this time, the power unit 42 is deenergized and thebrake 48 is actuated to not only stop the rotation of the truing roller11, but also to hold it in a fixed position.

The carriage 18 moves back toward the starting position thereof untilthe follower 15 is in contact with the profile 13 at the right-handcorner thereof, after which the truing roller 11 is again moved to theleft, truing the right-hand corner, the peripheral face and theleft-hand corner of the grinding wheel 12, after which the mechanism isdeenergized.

It is to be understood that during the first pass across the grindingwheel 12 by the truing roller 11, since the truing roller 11 isrotating, the truing operation will be a rough truing operation.However, since the truing roller is fixed against rotation when makingthe return pass across the grinding wheel 12, it will be seen that thesecond passperforms a light truing operation. Thus, the grinding wheel12 is reshaped to the desired contour and at the same time provided withthe desired finish without an undue wearing away of the truing roller.

It is to be understood that in view of the specific configuration of thetruing roller and the fact that it rotates about an axis parallel to theaxis of the grinding wheel 12, it is possible for the truing roller tobe fixed against rotation during the reverse pass thereof across thegrinding wheel 12 so that not only may the peripheral face of thegrinding wheel 12 be dressed while the truing roller is fixed againstrotation, but also the two corners thereof.

Although only a preferred embodiment of the invention has beenspecifically illustrated and described herein, it is to be understoodthat minor variations may be made in the truing mechanism and theoperation thereof without departing from the spirit of the invention.

I claim:

1. A mechanism for truing a grinding wheel having a peripheral grindingface merging with rounded corners, said mechanism comprising a truingroller, means for moving said truing roller along a path correspondingto the profile of the grinding face and corners first in one directionand then in return, means for rotation said truing roller during themovement thereof along said path in said one direction to therebyperform a relatively heavy initial truing operation, and means forstopping said truing roller at the end of movement in said one directionand for holding said truing roller against rotation during said returnmovement thereof along said path including said grinding wheel cornersto thereby perform a relatively light final truing operation on both thegrinding face and corners of the grinding wheel.

2. The truing mechanism of claim 1 wherein said truing roller has anaxis of rotation disposed parallel to the axis of rotation of thegrinding wheel.

3. The truing mechanism of claim 1 wherein said truing roller has anaxis of rotation disposed parallel to the axis of rotation of thegrinding wheel, and said truing roller is in the form ofa thin wheelhaving rounded corners.

4. The truing mechanism of claim 1 wherein said truing roller is in theform of a thin wheel having rounded corners.

5. The truing mechanism of claim 1 wherein said means for stopping andholding said truing roller against rotation includes a brake for bothstopping the rotation of said truing roller and holding said truingroller against rotation.

65. The truing mechanism of claim 1 wherein said means for moving saidtruing roller along said path includes a fixed profile and a followerhaving nonrotational sliding contact with said profile, and saidfollower being of a contour corresponding to the face contour of saidtruing roller.

7. A method of truing a grinding wheel having a peripheral grinding facemerging into rounded corners, said method comprising the steps ofsubjecting the grinding wheel to a rotatable truing roller and roughtruing the peripheral face and rounded corners thereof while moving thetruing roller in one traverse direction, stopping the rotation of thetruing roller of said movement and holding said roller against rotationand when subjecting the grinding wheel to the nonrotating truing rollerand lightly truing the peripheral face and rounded corners thereof whilemoving the truing roller in a reverse traverse direction.

8. The method of claim 7 wherein said truing roller is rotated about anaxis parallel to the grinding wheel axis during the rough truing.

9. The truing mechanism of claim 1 wherein said truing roller is in theform of a wheel having rounded corners.

10. A mechanism for truing a grinding wheel having a peripheral grindingface merging with rounded corners, said mechanism comprising:

a. a diamond impregnated truing roller rotatable about an axis parallelto the axis of said grinding wheel,

b. means for moving said truing roller axially along a pathcorresponding to the profile of the grinding face and corners, first inone direction and then in the return direction,

c. a profile bar,

d. a follower in contact with said profile bar and movable with saidtruing roller for guiding said roller along said path,

e. means for rotating said truing roller during the movement thereofalong said path in said one direction to thereby perform a relativelyheavy initial truing operation,

f. and means for stopping said truing roller at the end of movement insaid one direction and for holding said truing roller against rotationduring movement thereof in said return direction along said pathincluding said grinding wheel corners to thereby perform a relativelylight finish truing operation on both the grinding face and corners ofsaid grinding wheel.

1. A mechanism for truing a grinding wheel having a peripheral grindingface merging with rounded corners, said mechanism comprising a truingroller, means for moving said truing roller along a path correspondingto the profile of the grinding face and corners first in one directionand then in return, means for rotation said truing roller during themovement thereof along said path in said one direction to therebyperform a relatively heavy initial truing operation, and means forstopping said truing roller at the end of movement in said one directionand for holding said truing roller against rotation during said returnmovement thereof along said path including said grinding wheel cornersto thereby perform a relatively light final truing operation on both thegrinding face and corners of the grinding wheel.
 2. The truing mechanismof claim 1 wherein said truing roller has an axis of rotation disposedparallel to the axis of rotation of the grinding wheel.
 3. The truingmechanism of claim 1 wherein said truing roller has an axis of rotationdisposed parallel to the axis of rotation of the grinding wheel, andsaid truing roller is in the form of a thin wheel having roundedcorners.
 4. The truing mechanism of claim 1 wherein said truing rolleris in the form of a thin wheel having rounded corners.
 5. The truingmechanism of claim 1 wherein said means for stopping and holding saidtruing roller against rotation includes a brake for both stopping therotation of said truing roller and holding said truing roller againstrotation.
 6. The truing mechanism of claim 1 wherein said means formoving said truing roller along said path includes a fixed profile and afollower having nonrotational sliding contact with said profile, andsaid follower being of a contour corresponding to the face contour ofsaid truing roller.
 7. A method of truing a grinding wheel having aperipheral grinding face merging into rounded corners, said methodcomprising the steps of subjecting the grinding wheel to a rotatabletruing roller and rough truing the peripheral face and rounded cornersthereof while moving the truing roller in one traverse direction,stopping the rotation of the truing roller of said movement and holdingsaid roller against rotation and when subjecting the grinding wheel tothe nonrotating truing roller and lightly truing the peripheral face androunded corners thereof while moving the truing roller in a reversetraverse direction.
 8. The method of claim 7 wherein said truing rolleris rotated about an axis parallel to the grinding wheel axis during therough truing.
 9. The truing mechanism of claim 1 wherein said truingroller is in the form of a wheel having rounded corners.
 10. A mechanismfor truing a grinding wheel having a peripheral grinding face mergingwith rounded corners, said mechanism comprising: a. a diamondimpregnated truing roller rotatable about an axis parallel to the axisof said grinding wheel, b. means for moving said truing roller axiallyalong a path corresponding to the profile of the grinding face andcorners, first in one direction and then in the return direction, c. aprofile bar, d. a follower in contact with said profile bar and movablewith said truing roller for guiding said roller along said path, e.means for rotating said truing roller during the movement thereof alongsaid path in said one direction to thereby perform a relatively heavyinitial truing operation, f. and means for stopping said truing rollerat the end of movement in said one direction and for holding said truingroller against rotation during movement thereof in said return directionalong said path including said grinding wheel corners to thereby performa relatively light finish truing operation on both the grinding face andcorners of said grinding wheel.